An image capturing device, having an image correcting function of correcting a captured image (an image of a subject such as a white board, a book, etc. captured by the device) as if the subject were shot from the front even when the subject is shot from a direction oblique to the front of the subject, is well known today. Such an image capturing device is equipped with a correction means which corrects the captured image as if the subject were shot from the front by detecting the three-dimensional shape of the subject based on the captured image of the subject. A portable digital camera provided with such a correction means has been disclosed in, for example, FIG. 1, etc. of Japanese Patent Provisional Publication No.HEI09-289611 (hereinafter referred to as a “document No. 1”).